Page:Popular Science Monthly Volume 7.djvu/780

760 these one was on the gar-pike. The garpike is known to science as a very ancient type of ganoid fish—a sort of living fossil. The young gar has two tails, the one serpent-like and the other fish-like. The former is snake-like in motion as well as in form. It is largest and most active in the very young. As the fish grows, it aborts, and at adult age it is obsolete. Prof. Wilder's investigations show that this temporary tail is a vestige, a reminiscence, a survival. The ancestor of the gar was a reptile, and the young fish still carries the ancestral reptilian tail. Another paper by the same author was on—

The Sirenia.—The name we have borrowed from Greek mythology, according to which the sirens were young maidens who sat on the shores of a certain island near Italy, and "sang with bewitching sweetness songs that allured the passing sailor to draw near, but only to meet with death." Why the manatee and the dugong should be called sirenia is not apparent on the surface, for they are not graceful, neither are they sweet singers; besides, they bear no enmity to the human race. Externally the sirenia are whale-like, but internally they are pachyderm-like. Prof. Wilder has dissected a fœtal dugong (secured in Australia by Prof. Ward), and from a study of its structure he concludes that the sirenia are not modified whales, but modified pachyderms, and that they are descended from some ancient hippopotamoid quadruped.

Porcelain-Clay.—A paper was read by Prof. Cox, Indiana State Geologist, on a white clay resembling kaolin, lately discovered in Lawrence County, Indiana. A full synopsis of this paper was published in the Tribune, from which we derive the following particulars: The LawrecneLawrence [sic] County bed of porcelain-clay occupies the position of the Archimedes limestone belonging to the Chester group. This limestone has been entirely removed where the clay is found, by the action of water charged with hydrated silicate of alumina and carbonate of protoxide of iron. The water which held these substances in solution is supposed to have contained alkaline carbonates, with carbonic acid in excess. It is thus that the water was enabled to dissolve the limestone, and by an interchange of chemical constituents, the hydrated silicate of alumina was precipitated and the lime carried off in solution. The carbonate of protoxide of iron also continued in solution until it met with a sufficient amount of oxygen for its peroxidation and precipitation. The upper portion of the clay, from one to twelve inches in thickness, is of a light cream-color, free from grit and laminated. Then follow from four to five feet of pure white clay, also free from grit. Beneath this is a clay of similar quality, but slightly stained at the joints with oxide of iron. Prof. Cox calls the white clay Indianaite; it has a composition of 12 to 14 per cent, water, 42 to 45 per cent, silica, and 36 to 39 alumina. The area of the deposit is known to be at least 42 acres, and there is little doubt that it is much more extended. Indianaite is now used in the porcelain potteries at Cincinnati, and ware made of it is fully equal to the best English ironstone pottery.

Are Potato-Bugs poisonous?—A paper by Augustus R. Grote and Adolph Kayser stated the results of an investigation of the supposed poisonous properties of the potato-bug. A quantity of the bugs were submitted to distillation with salt-water, so as to increase the temperature, the product being four ounces of liquid from one quart-measure of the bugs. This liquid had an alkaline reaction, owing to the presence of free ammonia and carbonate of ammonia. It was perfectly clear, and had a very offensive odor. A tincture of the daryphora was next prepared, the bugs having been digested for twenty-four hours in alcohol, which was then evaporated at a gentle heat. The tincture had a decided acid reaction, was brown in color, odor not offensive. On introducing into the stomach of a frog about half a cubic centimetre of the liquid and of the tincture separately, no effect was observed. Hypodermic injection of the distilled liquid was in like manner unattended by injurious results, but the tincture proved fatal when administered in this way. The leg, into which the tincture was injected, was quickly paralyzed, and in thirty minutes the heart had ceased to beat. This tincture, though highly concentrated,